Archives for July 2018

IPM Update 7/11/18

Sweet Corn

European corn borer (ECB) moth catches in black light traps continue to be very low. There will be no map in this edition due to insufficient catch.  There have been isolated incidents of new feeding in the far south of the state, but generally, the threat to corn should be low until the second flight begins in earnest.  Once plants hit full tassel, any ECB larvae present will move downward on the stalk and re-enter the plant near the area where ears are forming.  This can result in direct injury to the ear.  Growers should consider an insecticide application at the full tassel stage to target ECB larvae as they migrate downward.  This application can eliminate larvae that have escaped any earlier insecticide applications. [Read more…]

Potato | Tomato Disease Forecast 7-9-18

Click to View | Download Report 7-9-18

Potato Disease Forecasting Report

We will be tracking DSVs for Late blight development and calculating P-days for initiating the first early blight fungicide application.

The first late blight fungicide application is recommended once 18 DSVs accumulate from green row. Green row typically occurs around the first week in May in southern NJ. An early season application of a protectant fungicide such as mancozeb (Dithane, Manzate, Penncozeb) or Bravo (chlorothalonil) as soon as the field is accessible is suggested. Please be vigilant and keep a lookout for suspect late blight infections on young plants. No late blight has been reported in our region to date.

Remember the threshold for P-days is 300!  Once 300 P-days is reached for your location, early blight fungicide applications should be initiated. Growers who are interested in using this model should choose the location above that is closest in proximity to their farming operation and should regularly check the Cornell NEWA website (http://newa.cornell.edu) where this information is compiled from. Click on Pests Forecasts from the menu, select your weather station, and click on tomato diseases, set accumulation start date, and a table of daily and total DSVs will be generated.

Tomato Disease Forecasting Report

Disease severity values (DSVs) for early blight, septoria leaf spot, and tomato anthracnose development are determined daily based on leaf wetness (due to rainfall, dew) and air temperature.

On a daily basis DSV values can range from 0 to 4 where 0 = no chance for disease development to 4 = high chance for disease development. DSVs are accumulated during the production season.

Fungicide applications are based on an individually determined DSV threshold. The first fungicide application for the control of these three diseases is not warranted until 35 DSVs have accumulated from your transplanting date. After that, growers can base fungicide applications on different DSV thresholds.

Reports generated by Ryan Tirrell

Rutgers, The State University of New Jersey

Potato | Tomato Disease Forecast 7-6-18

Click to View | Download Report 7-6-18

Potato Disease Forecasting Report

We will be tracking DSVs for Late blight development and calculating P-days for initiating the first early blight fungicide application.

The first late blight fungicide application is recommended once 18 DSVs accumulate from green row. Green row typically occurs around the first week in May in southern NJ. An early season application of a protectant fungicide such as mancozeb (Dithane, Manzate, Penncozeb) or Bravo (chlorothalonil) as soon as the field is accessible is suggested. Please be vigilant and keep a lookout for suspect late blight infections on young plants. No late blight has been reported in our region to date.

Remember the threshold for P-days is 300!  Once 300 P-days is reached for your location, early blight fungicide applications should be initiated. Growers who are interested in using this model should choose the location above that is closest in proximity to their farming operation and should regularly check the Cornell NEWA website (http://newa.cornell.edu) where this information is compiled from. Click on Pests Forecasts from the menu, select your weather station, and click on tomato diseases, set accumulation start date, and a table of daily and total DSVs will be generated.

Tomato Disease Forecasting Report

Disease severity values (DSVs) for early blight, septoria leaf spot, and tomato anthracnose development are determined daily based on leaf wetness (due to rainfall, dew) and air temperature.

On a daily basis DSV values can range from 0 to 4 where 0 = no chance for disease development to 4 = high chance for disease development. DSVs are accumulated during the production season.

Fungicide applications are based on an individually determined DSV threshold. The first fungicide application for the control of these three diseases is not warranted until 35 DSVs have accumulated from your transplanting date. After that, growers can base fungicide applications on different DSV thresholds.

Reports generated by Ryan Tirrell

Rutgers, The State University of New Jersey

IPM Update 7/04/18

Sweet Corn

European corn borer (ECB) moth catches in black light traps remain very low; situation unchanged from last week.  There will be no map in this edition due to insufficient catch.  Incidents of feeding are declining as infested plantings proceed to silk and whorl stage corn has not been exposed to egg laying.  We should be in a period relatively free of whorl infestations now.  The next whorl infesting pest will be fall armyworm (FAW).  As yet, no infestation of this pest have been detected.    [Read more…]

Post-bloom Insect Pest Control Recommendations

As we approach the end of bloom, growers should consider the need for any post-bloom applications. The main pest targets for these applications are mainly Sparganothis fruitworm and spotted fireworm.

Sparganothis fruitworm (SPARG) – If your farm has high pheromone trap counts, you should consider managing this pest as soon as bees are removed. The timing for this 1st post-pollination spray is at 2 weeks after peak pheromone trap catches, which usually coincides with this time of the year.

Spotted fireworm (SFW) – SFW is one of the most important pests in New Jersey. Male SFW moth catches typically peak in the second through third week in June. Although trap catches give an indication of population size, these numbers not always correlate with numbers of egg masses. This insect becomes a problem in “weedy” beds because female moths lay their eggs predominantly on weeds. Thus, growers need to monitor for the presence of SFW egg masses on weeds (broadleaf species and grasses). Keeping beds clean from weeds will keep this insect under control. Egg masses should be hatching by now. SFW larvae from this generation feed on foliage as well as fruit.

Control Options – Insect Growth Regulators (IGRs) (e.g. Intrepid and Confirm) are effective against SPARG. Alternatively, if you have used IGRs intensively (e.g. last year and this year as a pre-bloom or bloom spray), and would like to rotate with other chemistries, you may want to use Altacor, Delegate, or the broad-spectrum insecticides Diazinon, Imidan, or Lorsban. Broad-spectrum insecticides are also a choice if you have high blunt-nosed leafhopper populations (see below) because Intrepid, Delegate, and Altacor will have no effect against this insect. IF YOU ARE AN OCEAN SPRAY (OS) GROWER PLEASE CHECK RESTRICTIONS ON THE USE OF THESE INSECTICIDES. Lorsban in particular can’t be used by OS growers after bloom due to maximum residue limits (MRLs) for exporting cranberries. If you are an OS grower and want to use a post-bloom application to control SPARG then Delegate, Altacor, Diazinon (no aerial application allowed), or Imidan would be your options.

Blunt-nosed leafhoppers– The best timing for controlling blunt-nosed leafhoppers is before bloom when they are immatures. At this time of the year, most of the population are adults and already laying eggs. If you did not spray before bloom and have a high leafhopper population, you may consider a post-bloom application to prevent from an increase in population size. You may also consider spraying next year to control for those immatures that will emerge from the already laid eggs. I list the best products against leafhoppers. As indicated above, if you are an OS grower please check insecticide use restrictions based MRLs.

Recommendations for leafhopper control

Recommendations for leafhopper control

Vegetable Disease Update – 7/3/18

  • Cucurbit downy mildew has been confirmed on cucumber in southern NJ this week. This is the first report in the state this growing season. All cucumber growers should scout their fields on a regular basis and consider adding a downy mildew specific fungicide to their weekly maintenance sprays.
  • The 2018 FRAC Table for Cucurbit Downy and Powdery Mildew Control in the mid-Atlantic Region can be found and downloaded for FREE here.
  • There have been no new reports of late blight in the region.
  • Basil downy mildew has been reported in retail pots and in fields in southern New Jersey.
  • Bacterial leaf spot and Phytophthora blight have been confirmed in pepper.
  • Cercospora leaf spot was found on fenugreek this past week.
  • The extremely hot, dry weather this past week should help mitigate diseases such as downy mildew. Remember, copper applications when temperatures and relative humidity are above 90 may cause phytotoxicity in some crops.